I need help please, as this math is beyond me
For capstan , bollard frictions.
I even have trusted document that has let me make sense and understand many things of knots and bollard frictions.
.Jrre.org/att_frict.pdf
gives .25 coefficient for nylon rope on aluminum pipe for brake force.
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I have made this chart, the paper shows brake force same on larger pipe, friction by degrees of contact.
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I am seeking to mostly fill in 180° on to table assuming same coefficient to show pattern.
But , would also like to show 90°, 360°, 720° please.
Wouldn't mind knowing how to calc or some tool even.
This would help immensely to define more about working knots and rigging, thank-you!
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"Nature, to be commanded, must be obeyed" -Sir Francis Beacon

If you have Microsoft Excel available to you,
try placing the data into a graph and fitting an exponential trend-line through the data.
This will give you an equation fitting the data.

However I doubt that, in practice, the actual friction is as precisely matched to the theoretical friction, as this table suggests.

For a practical estimate of the friction, I would suggest that a simple linear interpolation (straight line between the adjacent points in the table) will suffice.

Having said that, the gap between 5pi and 7pi is a bit large,
which will result in a simple linear estimate being less than ideally accurate.
If data in this region is vital, then the more accurate exponential fit is indicated.